Over what body of water did most roman trade routes cover

Your answer would be, I believe the Mediterranean Sea.

Goods were continually transported throughout the Roman Empire. The most effective way to transport goods was by sea. The type of ship commonly used by the Romans was known as a Corbitas. It is described as a round-hulled ship with curving prow and stern. Depending on its size, it could carry cargo weighing between 70 and 350 tons. Ships could carry as many as six hundred passengers or six thousand jars of wine, oil, or other liquids. Ships transported more goods in a shorter amount of time than could be moved overland. For example, it took only two to three weeks by ship to go from Egypt to Rome. In order to increase the effectiveness of shipping, the Romans developed deep harbors at key locations. One of the largest harbors was at Ostia, about 15 miles from Rome on the Mediterranean Coast. In A.D. 50, a lighthouse was set up at Ostia to guide sailors. At its peak, Rome set up lighthouses in forty different locations to aid sailors.

Hope that helps some : )

the answer is b: an economic crisis throughout the country.